The present invention is applicable to the field of microdevices and is more specifically applicable to electrostatic microdevices.
Microactuators, and particularly electrostatic microactuators, have heretofore been provided. See, for example, U.S. Pat. No. 5,998,906 and International Publication Number WO 00/36740. Such microactuators can be utilized in microdevices, for example in the telecommunications industry and in the data storage industry, for moving optical elements. See, for example, International Publication Number WO 00/36447 and U.S. Pat. No. 6,134,207. It has been found that applied external accelerations can undesirably effect the performance of microdevices employing microactuators.
What is needed, therefore, is a microdevice that is substantially mechanically balanced such that an element moved thereby does not appreciably move when subjected to external accelerations.
What is also needed is a rotary electrostatic microactuator that rotates about a pivot point disposed outside the confines of the microactuator.
In general, a balanced microdevice is provided that includes a substrate and at least one comb drive assembly having first and second comb drive members. The first comb drive member is mounted on the substrate and the second comb drive member overlies the substrate. At least one spring member is provided that has a first end portion coupled to the substrate and a second end portion coupled to the second comb drive member. The first comb drive member has a plurality of spaced-apart first comb drive fingers and the second comb drive member has a plurality of spaced-apart second comb drive fingers. The second comb drive member is movable between a first position in which the first and second comb drive fingers are not substantially fully interdigitated and a second position in which the first and second comb drive fingers are substantially filly interdigitated. A counterbalance is carried by the substrate and coupled to the second comb drive member for inhibiting undesirable movement of the second comb drive member in response to externally applied accelerations to the microdevice.